The article continues the discussion on the urgency of Marx's ideas for modern Russia started in No 5 and 6 by the article of E. Gajdar and V. Mau "Marxism: between the Scientific Theory and "Secular Religion" (Liberal Apologia)" and continued in No 7 by the article of A. Buzgalin and A. Kolganov "Do We Need Liberal Marxism? " In the first part of the article questions of economic theory, first of all the difference in treatment of the category of production relations between Marx and domestic scientists are considered. The author pays attention to treatment of the category "direct producer": for Marx this one is the businessman making economic decisions and responsible for their success with his property. Besides it is underlined that Marx had not finished the work on the second and the third volumes of "Capital", and most likely the marginalist revolution could have played a leading role here. Inadequate translation of some of the terms in Russian (sometimes deliberate) can also be blamed for distortion of Marx's heritage. To the author's opinion initial installation is important in consideration of Marx's theory: the choice of political approach exaggerates revolutional ideas of his doctrine (at the end of his life Marx had rejected many ideas and called "Manifest" "party excrement of twenty years' prescription"). The scientific approach will allow the scientist for example to continue the analysis of submission of labor to capital, to investigate qualitative aspects of the labor theory of cost.